The idea that breakfast is the most important meal of the day traces its roots to industry advertising. A new study published in the Journal of the American College of Cardiology wants us to believe that skipping breakfast increases our risk of dying from cardiovascular disease. Other studies suggest that skipping breakfast increases your risk of being overweight, having high blood pressure or elevated bad cholesterol, and diabetes. Let’s take a look at the newest mining of a database.
They looked at roughly 6500 adults who participated in the National Health and Nutrition Examination Survey (NHANES) who completed surveys and were examined during the period 1988 to 1994 when breakfast eating was surveyed. The researchers excluded those with cardiovascular disease or cancer at baseline or those dying within a year of the study, the pregnant and those with missing breakfast information. The frequency of eating breakfast ranged from every day to some days, rarely or never. So as is often the case the exposure variable, eating breakfast, is assessed only once in the median 18.8 years of follow-up and is, therefore, a bit fuzzy.
Perhaps a more significant limitation was that those individuals skipping breakfast were often former smokers, heavy drinkers, physically inactive, obese, with higher total blood cholesterols and had poorer dietary quality than those who ate breakfast daily. When fully statistically adjusted, those individuals skipping breakfast had a 19% greater chance of dying from any cause and an 87% higher risk of dying from cardiovascular disease, specifically strokes rather than heart disease. A careful look at the data showed that this increased risk was statistically significant only when comparing everyday breakfast eaters to those who never ate breakfast at all, and just for the risk of stroke. For those some days and rarely eating breakfast groups, there was no statistical benefit.
The second glaring limitation of the study, after not truly knowing the frequency of breakfast eating, is that the researchers had no information on what was being eaten. Are we talking about a cup of yogurt and almond milk, or a few eggs, bacon, whole wheat toast (after all, you have to be careful what you eat) all washed down with a glass of orange juice and lots of coffee?
Given the observational nature of the study and the significant limitations to the frequency and composition of breakfast, skipping breakfast is certainly not causal, and it is hard to say that it is associated. But as the accompanying editorial points out, “what is clear is that a pattern of skipping breakfast identifies a population at risk.” It is a marker, not a measure. As a marker it may have value in developing more precise calculations of risk. But simply eating breakfast will not alter smoking, drinking, sedentary behavior and poorer dietary choices this “marked” population already makes.
Source: Association of Skipping Breakfast with Cardiovascular and All-Cause Mortality Journal of the American College of Cardiology DOI: 10.1016/j.jacc.2019.01.065